Manufacture of base assemblies for electric discharge tubes



. S. J. MANUFACTURE OF BASE ASSEMBLIES FOR NOV. POWERS ELECTRICDISCHARGE TUBES Filed Jan. 12, 1944 Patented Nov. 30, 1948 g MANUFACTUREOF BASE ASSEMBLIES FOR ELECTRIC DISCHARGE TUBES Stephen John Powers,London, England, assignor,

. a by mesne assignments, to International Standard ElectricCorporation, New York, N. Y., a

, 1i corporation of Delaware Application'JanuarylfZ, 1944, Serial No.517,945 In-Great Britain April 21, 1943 Claims. (01. 49-78)v v 1 2 Thepresent invention concerns improved meth sembly with the conductor wiressealed to the ods of sealing the electrode leads through the disc; and

envelope of an electric vacuum or gas-filled tube of any type. i

It is applicable to any device or tube such as a cathode ray tube, forexample, or a thermionic valve having electrodes mounted inside anenvelope, which envelope may be exhausted or filled with gas at anypressure. It has previously been common practice in such tubes to sealthe leads for the electrodes through a stem or press of glass, orceramic material, or the like,.or through a substantially flat base, thestem or base being then sealed to the envelope.

' It is proposed to use a flat disc or base of glass provided with acentral exhaust tube and formed with U-shaped radial slots around theperiphery. The electrode conductors comprise short wires or rods eachcarrying a small glass bead. The'wires are placed with the beads in theslots, and the base is inserted into the neck of the envelope of thedevice, and the wires are sealed into the base and the base to theenvelope in one operation.

One of the advantages of the arrangement is that it enables theelectrode conductors to. be spread apart as widely as possible, so thatthey may lie in a circle not much smaller than the cross-section of theneck of the tube. The present invention employs another method ofsealing the leads through a disc of similar type which does not involvesealing the disc to the envelope of the tube in the same operation. Theadvantage of having the conductors spread out by the maximum amount isretained.

The invention accordingly consists in the method of making a baseassembly for an electric vacuum or gas filled tube which compriseslocating conductor wires in peripheral slots of a disc of fusiblematerial, softening the disc by heat, squeezing it between a pair ofdies, and rolling a tool around the edge of the disc in sucha mannor asto close the slots on the wires so that they are hermetically sealedthrough the disc.

The invention will be described with reference to the accompanyingdrawings in which:

Figure 1 is a top view of a glass disc or base for a vacuum tube;

Figure 2 is a section taken on line 2-2 of Figure 1;

Figure 3 is a side elevation of a wire electrode conductor carrying aglass bead;

Figure 4 is a longitudinal section of the base and conductor wiresassembled in a die to show how the wires are fused to the disc;

Figure 5 is a top view of the finished base as- Figure 6 is a sectiontaken on line 66 of Figure 5.

Referring to Figures 1 and 2, the glass disc or base comprises acircular disc i 0, to the centre of which is sealed an exhaust tube H.Around the periphery of the disc are a number of rounded slots I2 havingdepressed edgesor rims it. This form may be produced, for example, bytaking a plain circular disc, heating it sufficiently to soften theglass, and then pressing suitable wires (or the like) inwards anddownwards from the edge of the disc. This produces rounded slots of thekind shown. The disc may, however, be formed in other ways, such as in amoulding tool.

Figure 3 shows one of the electrode conductors.

. It comprises a-metal wire or rod M having fused thereon a small glassbead l5.

The method of sealing the wires to the disc according to the inventionis shown in Figure l. A lower die 16 is provided with a central channelfor the exhaust tube H and with a numb-er of smallerblind holes i1arranged around a circle,

inthedisclll."

The disc It] is placed on the lower die l6 with the exhaust tube Iiinserted into the central channel of the die, the slots l2 registeringwith the holes H. The Wires M are then inserted in the holes I! with thebeads l5 located in the slots l2. An upper die [8 having holes l9corresponding to the holes I! is provided. Heat is applied in anyconvenient manner to melt the glass of the disc, and the upper die isbrought down onto the disc, as shown in dot-dash lines it, with theupper ends of the wires M in the holes is. The glass is pressed intocontact with the beads i5 and fuses thereto, and some is expelledsideways forming a ridge or heading 20. During this operation a rollertool 2| with an appropriately shaped groove 22, is run around the edgeof the base ill to form the beading 20, and to ensure that the slots areclosed up and that the melted glass flows all around the beads l5, sothat there is formed a complete circular disc with the wires sealedthrough it, as shown in Figures 5 and 6.

The base assembly so formed is suitable for and located so as tocorrespond with the slots 12 any electric device having electrodesinside an envelope. The electrodes may be mounted on the wires l4, andthe disc may then be sealed around the beaded edge to an appropriateenvelope in any convenient way, and the envelope may be exhausted orfilled with gas through the sealing to the material of the disc l0":

Furthermore, the exhausttube is not essential and could be omitted if asuitable-tube is'prjo- The head IS on each of the electrode conductorsit should, of course, be of fusible materialappropriate for" videdsomewhere else in the envelope of the:

device. the lower die would not be necessary.

What is claimed is:

1. The method of making a base assembly fer an electric discharge tubewhich comprises 10-- cating conductor wires in peripheral slots of adisc of fusible material;v softening thex-disc: by heat, squeezing thedisc to press the disc into contact with the wires,v and applying a'rolling action around the edge of the disc in? such :a

manner as: to close" the slots" around the: wires so that the" wires arehemieticallysealed in the disc t 2; The method'of makingla base assemblyfor eatinga number: ofconductor: wires each provided with a fusible'bead in spaced. peripheral slots in a disc: of fusible: insulating:material; so that the b'ead's register within the: slots applw in'gheatto melt the fusible material;- pressing the disc into contact withthe beadsandztoexe pel a peripheral ridge" oithe fusible material, andapplying a rolling action around thetri'cl'ge of the disc to' form theridge and: tb press the molten insulatingmaterial: inwards s'o'as toclose the slots aroundithe-b'eads'.

3; The method of making a: base" assembly' for an?electricdischargetubewhich comprises form ing a plurality of spaced slotsaround the peripheryof a disc of fusible material holdin'gaip1urality of conductorwiresinfixed relation to each other and to the disc with the wiresextending In such a case the central channel of through the slots,heating the disc to fusing temperature, and squeezing the disc to pressthe fusible material around the wires in the slots and simultaneouslyrolling the rim of the disc to force: the fusible material around theWires and to produce a-uniformi rim: around said disc.

4. The method of making a base assembly for an electric discharge tubewhich comprises fusing spaced slots with depressed rims into theperiph'eryi-ofiadisc; holding a plurality of conduct'or'wiresin spacedfixed relation with each wire extendingg through one of the slots ofsaid discsheating: said; disc to fusing temperature,

"aind pressing: said: disc and simultaneously rolling the fusiblematerial around the rim of said disc tq jorce such. material around saidwires 'a'n electric' discharge tube, which: comprisesv '10- Y andproduces, uniform circular rim.

5, The method of making a base assembly for an' electric discharge tubecomprising placing a number of conductor wires in peripheraldepressions: located: in a: discof insulating: material, heatingthe discand applying pressure on the disc to force the insulating materialzintocontactwith the wires, and applying pressure around; the'pe*ripheraledge. of the disc to forcethe insulating material intosealedcontactwith the wires.

r STEPHEN! 'JQHN POWERSi V REFERENCES CITED;

, 'I he following references are of record" in the file of this patent:i

UNITED STATES PATENTS Number Name Date '850;02'9- Meeker :Apr: 9', 19107872530 Meeker: D'ec.i3; 1907 2395, 183 Franks Apr; 2', 1940 23345784Miller: Nov.:23, 1943 21339350 Goodale Jan. 25,-.1944

23403879 Horn-N -Feb. 8; 1944 v FOREIGN. PATENTS Numberv Country Date:

376,953: Italy l. e -Dec. I4, 1939

